1. Field of the Invention
This invention relates to manually driven piston pumps; specifically, to such pumps used for displacement and extraction purposes.
2. Brief Description of Prior Art
Retail stores commonly supply consumers with pumps for the cleaning, flushing and removal of debris from indoor and outdoor pipes. Gas and or water is used with these pumps to discharge the debris contained in them. These pumps are usually equipped with pistons that sacrifice flexibility for durability. As a result, these pistons are short lived and in regular need of repair or replacement. Many consumers are in need of a pump that not only addresses these problems but is also capable of extraction and or collection of samples as well.
Some pumps supplied by retail stores are pumps that must be installed as part of the pipes' flow system to function properly. These pumps are limited to the flushing of material from pipes using only a unidirectional flow pattern. In addition, they must be charged with a source of pressurized gas or water for flushing purposes to relieve plugging and to restore free flow. U.S. Pat. No. 1,769,061 to Hitcock (1930) submits an expensive construction that uses air injected into a pipe opening for flushing purposes. This design is a method of injecting rather than extracting using a piston of sort with no means of making pressure adjustments. U.S. Pat. No. 4,053,955 to Canham (1948) shows an expensive construction with a hydraulic plunger with springs attached. This construction opens into a clogged drain pipe for cleaning purposes and is also unidirectional with no extraction and piston adjustment capability. These and all previously referred to pumps suffer from a number of disadvantages:    1. These pumps are unidirectional. They are displacement pumps that do not lend themselves to retrieval by extraction.    2. These pumps have piston seals that, in some cases, may or may not be adjustable. Pumps with adjustable seals would require proper tools to make these adjustments. Depending on the purpose of their use, some of these pumps might require proper attire to make these adjustments to avoid contaminates. Proper attire, although it reduces the chance of contamination may also add to the cost factor. Extra costs are incurred in many cases. Pumps with piston seals that are not adjustable may require a new piston seal or complete pump replacement may be necessary.    3. These pumps are not suitable for use apart from the pipe environment. They are used primarily for the cleaning of pipes and or the unplugging of debris from these pipes.
It is an object of the present invention to provide:    1. A closure that is bidirectional and can be used for both displacement and extraction purposes.    2. A closure with an adjustable piston seal that permits regulation of the pump seal and minimizes replacement costs while at the same time eliminating the necessity to handle contaminated areas of the pump.    3. A closure that makes it possible to extract remnant from holes in soft sand and or the remnant from holes in soft soil.